This invention relates to a method and apparatus for applying thermal energy to biological tissue whereby tissue is converted to a denatured proteinaceous substance to join tightly approximated tissue segments, and, more particularly, to a method and apparatus for reconstructing severed tissue, including vessels and ducts by use of a clamp which is constructed to hold edges of the tissue in tight proximity while directing heat energy onto the tissue to denature the proteinaceous substance therein.
Optical energy has been used to convert biological tissue into a denatured collagenous substance for facilitating healing and wound closure. This healing technique is referred to generally as laser tissue welding. Examples of such laser tissue welding methods are described in U.S. Pat. Nos. 4,672,969, 4,854,320, 5,002,051, and 5,140,984. These methods deliver optical energy to tightly approximated tissue in the vicinity of a wound. This application of thermal energy results in the denaturation of tissue protein including collagen, with disruption of the cell walls which allow the intra- and intercellular fluids to mix. Additional heat further denatures this protein soup which binds together creating something akin to a "biological glue".
In many prior methods of optical energy wound closure, such energy is delivered through an optical fiber to the tissue being reconstructed. Typically one end of the fiber is connected to a laser that supplies optical energy to the wound site. Another end of the fiber is typically spaced a predetermined distance from the tissue, depending on the tissue type. A foot pedal or hand held device activates and deactivates the laser. The parameters such as intensity and duration of the optical energy are controlled so that substantially all of the tissue being heated is raised to a predetermined non-destructive temperature. The minimum predetermined temperature is one at which tissue is converted to a denatured collagenous substance. The maximum predetermined temperature is one at which water in the tissue boils.
Other methods known for healing and wound closure include suturing and stapling. These methods are often used in minimally invasive surgery in combination with various types of scopes, such as, for example, endoscopes, laparoscope, arthroscopes, etc. These scopes along with other medical equipment are inserted by a surgeon through incisions in the patient and then moved to the wound area being repaired. The scope is connected to a monitor so that the surgeon can view the procedure while the surgery is being performed.
Laser tissue welding may be used in minimally invasive surgery to repair vessels; however, conducting certain minimally invasive operations using current laser surgery techniques is long and tedious as the surgeon must weld at successive points along the circumference of the vessel or duct. This tissue welding process is further complicated as the distal end of the optic media that directs the laser doing the welding must be placed a predetermined distance to the tissue being reconstructed. If the distal end is not a predetermined distance from the area being reconstructed, the tissue would be temperature outside the aforementioned predetermined temperature sealing range. A drawback to prior welding methods is that it is difficult to place edges of tissue being repaired in close approximation. Placing the edges in tight proximity is necessary to insure proper denaturation and intercellular fusion of the tissue.
It is also desirable during surgery to occlude vessels. Occluding the vessel typically requires that clips or sutures be placed on the vessel to clamp the vessel shut. Clips, suture and staples left in the tissue are foreign bodies that can later have adverse effect on the patient.